Generally, among wrapping apparatuses that are used to automatically wrap a wrapping sheet such as a film around a work piece, a wrapping apparatus is known in which the film used for wrapping is positioned in a direction orthogonal to the transporting direction of the work piece, and by transporting the work piece such that it presses against the film, the work becomes covered by the film. The apparatuses described in Patent Documents 1 and 2 below are examples of this type of wrapping apparatus.
PATENT DOCUMENT 1: Japanese Patent No. 2723581
PATENT DOCUMENT 2: Japanese Patent Application, First Publication No. H10-194219
In the wrapping apparatus described in Patent Document 1, in order to feed a wrapped work piece to the interior of a pocket of a pocket conveyor, a nozzle having an aperture whose dimensions match the thickness of the work piece is placed so as to face the opening of the pocket, and the film is positioned in a direction that is orthogonal to the transporting direction of the work piece to the rear in the transporting direction of the work piece. By then pressing the work piece against the film and making them pass through the nozzle, the film becomes wrapped around so as to cover the work piece and the work piece is then placed inside a pocket.
In the wrapping apparatus described in Patent Document 2, a pair of floating rollers that are spaced the same distance apart as the pocket boxes are placed in the vicinity of openings in pocket boxes that are used to house work pieces that have been wrapped, and a film is positioned in a vertical direction in the same manner as in Patent Document 1 to the rear in the transporting direction of the work piece. By transporting the work piece in a horizontal direction so that it presses against the film and so that the two are made to pass between the floating rollers, the work piece is packaged in a wrapped state and is placed inside a pocket box.
However, in the wrapping apparatuses described in Patent Documents 1 and 2, the work piece passes through the inside of the nozzle and the pair of floating rollers while the film is being wrapped, and because the space between the nozzle and the floating rollers is a fixed size that is equal to the thickness of the work piece, if there are any irregularities in the size of the work piece, then gaps may remain between the work piece and the film causing defects such as residual air and wrinkling to be generated. Moreover, if there are any bumps and indentations in the surface of the work piece, then because gaps remain between the film and the work piece, in the same way, these cause residual air and wrinkling. Because of this, these wrapping apparatuses have the drawback that they do not make it possible to achieve tight wrapping of a work piece without any wrinkling being generated and without any residual air being left behind.
The present invention was conceived in view of the above described circumstances, and it is an object thereof to provide a wrapping apparatus that makes it possible to perform wrapping in which there is no wrinkling and in which no air remains between the work piece and wrapping sheet even if there are irregularities in the dimensions of the work piece or if there is unevenness in the surface of the work piece.